A conventional view in the U.S. is that, ceteris paribus, individuals with a behavioral health problem(s), such as drug addiction, consume excessive amounts of health care relative to individuals who do not have a behavioral health problem. Although little research has examined this issue employing quality data or contemporary statistical methods, a few recent studies have demonstrated that chronic drug users (i.e., weekly or more frequent use of illicit drugs during the previous year) generally consume more expensive health care (e.g., emergency room visits, inpatient hospital days), but less routine and preventative care (e.g., outpatient clinic and physician visits) (French, McGeary, et al., 2000; McGeary and French, 2000; French, et al., forthcoming). According to one study conducted on chronic drug users in Miami, Florida (French, McGeary, et al., 2000), the estimated differential in the cost of health services utilization may amount to over $1,000 per year. Given the need for current and nationally representative information on the type and cost of health services utilization by drug abusers, this research application will estimate differentials in utilization and cost of health services by chronic drug users relative to non-chronic drug users and non-drug users using the most recent public use file of the National Household Survey on Drug Abuse (i.e., 1999). The proposed secondary analysis study has important policy implications because little scientific information is available on the utilization and cost of health services by chronic drug users. Such information is crucial for policy makers, substance abuse program personnel, and health care providers as they consider and decide on addiction interventions. The research significance is also high because recent studies have used contemporary health services research methods to estimate the utilization and cost of health care for drug users. However, since these studies have analyzed regional data, it is important to determine whether the regional results are similar to estimates derived from national data. Finally, the examination of chronic drug users versus non-chronic drug users and all drug users contributes to the growing recognition among substance abuse researchers and treatment providers that drug users should not be treated as a 1 homogeneous group.